Abstract: Provided is a computer system capable of maintaining consistency of data stored in logical volumes. The computer system includes: a storage system including a disk controller which controls data read/write in a disk drive; and a host computer which transmits a request to the storage system, wherein the disk controller has a control unit and a storage unit, the disk drive has logical volumes which are data storing areas, the host computer sends a request directed to the logical volume and attribute information of the logical volume, the control unit wherein: executes the received request; the control unit stores, in the storage unit, the received attribute information in association with the logical volume; and decides to execute a following request which is made by the host computer to the logical volume in a case where the request meets the attribute information corresponding to the logical volume and is stored in the storage unit.

Abstract: In a system in which data employed by a computer is stored in a storage system, the storage system transfers this data to another storage system and a copy of the data is maintained in the other storage system, consistency of the copy is maintained even in the case of data written to the storage system by a computer, to which a write time is not applied. A source storage system, when a write time is applied to a write request, records the write time and applies this write time to the received write data and, when no write time is applied, applies the recorded write time to the received write data and transfers the write data with this write time applied thereto, to another storage system. The target storage system stores the write data in a logical volume in the target storage system in accordance with the write time.

Abstract: A storage control apparatus and a storage control method are provided wherein in a system having a plurality of disk systems and secondary disk systems at remote sites, the data transfer amount between a central processing unit and a disk system can be reduced when duplicate disk write is performed, the performance can be prevented from being degraded even if the distance between control units is elongated, and the intermediate results of a transaction are not left. A standard time is determined and a program is provided which instructs a secondary central processing unit to reflect only update information having a write time older than the standard time, upon a logical disk in the secondary disk system.

Abstract: In the data transfer method between a couple of computer nodes in the related art, an overhead for the waiting between programs to conduct the data transfer is considerably large. In the present invention, a first program to transmit data stores the data to the main storage area in the desired time interval. A second program to receive data refers to the above area using RDMA in the desired time interval. Otherwise, the second program to receive data refers to the main storage in the desired time interval. A first program to transmit data stores data to above area using RDMA in the desired time interval. Moreover, in order to detect the passing between the write and read operations, an identifier is provided to each record and the access sequence of the identifier and record is inverted in the read and write operations. Or, an identifier and an error checking code are added to each record.

Abstract: To provide a computer system constituting a multitarget array and utilizing a remote copy technique for backing up data, in which when a failure occurs in a primary site, a new pair is formed between remaining two secondary sites without copying all data. A first secondary site is associated with the primary site by synchronous remote copy. A second secondary site is associated with the primary site by asynchronous remote copy. A storage system of the first secondary site includes a difference bitmap indicating an area to which data has been written from a host computer. When a failure occurs in a host computer of the primary site, only data of an area indicated by the difference bitmap is transferred to a storage system of the second secondary site.

Abstract: During the normal operation state of a computer system 1000, the data stored in a primary storage system 200P is copied to an intermediate storage system 200I via synchronous copying and the data stored in the intermediate storage system 200I is copied to a secondary storage system 200R via asynchronous copying. During the reverse operation state, however, the data stored in the secondary storage system 200R is copied to the intermediate storage system 200I via asynchronous copying and the data stored in the intermediate storage system 200I is copied to the primary storage system 200P via synchronous copying. In this way, practical remote copying can be carried out in a computer system in which three or more storage devices are installed at different locations and connected serially.

Abstract: Composition of a consistency group is changed easily without releasing a volume pair of the consistency group concerning a remote copying system and a remote copying method using a sequence number. In order to change the composition of the consistency group, predetermined data sent from a data sending side after the relevant change is received. At that time, a reflection operation of the predetermined data on a logical storage area is started on a data receiving side after reflection of the predetermined data sent from the data sending side before the relevant change on the logical storage area is terminated.

Abstract: In the conventional storage system, consistency is ensured only for writing from a single storage. Asynchronous remote copying and local replication are also alternately suspended in the conventional system, so that the suspension time increases and the volume in which consistency is obtained becomes old. Two local replicas are prepared, for a volume containing stored data that is transferred from the main site by asynchronous remote copying, in the storage at the sub-site. Each pair of local replicas is alternately suspended by a time-specific suspension command according to the time of the timestamp attached to the write data, and replica data in which the time sequence is secured is continually prepared. When a failure occurs at the main site, the data is recovered using the replica data.

Abstract: Even when a host does not give a write time to write data, consistency can be kept among data stored in secondary storage systems. The present system has plural primary storage systems each having a source volume and plural secondary storage systems each having a target volume. Once data is received from a host, each of the plural storage systems creates write-data management information having sequential numbers and reference information and sends, to one of the primary storage systems, the data, sequential number and reference information. Each of the secondary storage systems records reference information corresponding to the largest sequential number among serial sequential numbers and stores, in a target volume in an order of sequential numbers, data corresponding to reference information having a value smaller than the reference information based on the smallest value reference information among reference information recorded in each of the plural secondary storage systems.

Abstract: A remote copy system includes a plurality of first storage systems and a plurality of second storage systems. Each first storage system assigns a sequential number to write data received from the host and sends the write data with the sequential number to the second storage system. One of the first storage systems defers the processing of the write request received from the host and instructs each of the first storage systems to create a marker, whereupon each of the first storage systems defers the processing of the write request, creates a marker including a sequential number and having a marker number, and sends the marker to the second storage system. Each of the second storage systems, when receiving a marker from the first storage system, stores the marker number included in the marker.

Abstract: In a computer system with a plurality of levels of cache storage, a cache control method prevents data duplication among the levels of cache storage to increase cache storage utilization. A high-level cache staging unit stages reads data from a disk unit, stages the data to a high-level cache, and instructs to destage the data, which has been read, from a low-level cache. A high-level cache destaging unit writes data to be destaged to the disk unit, instructs to stage the data, which has been written, to the low-level cache, and destages the data from the high-level cache. A low-level cache staging unit stages a data, which is written by the high-level cache destaging unit, to the low-level cache. A low-level cache destaging unit destages a data, which is instructed by the high-level cache staging unit, from the low-level cache.

Abstract: In a system in which data employed by a computer is stored in a storage system, the storage system transfers this data to another storage system and a copy of the data is maintained in the other storage system, consistency of the copy is maintained even in the case of data written to the storage system by a computer, to which a write time is not applied. A source storage system, when a write time is applied to a write request, records the write time and applies this write time to the received write data and, when no write time is applied, applies the recorded write time to the received write data and transfers the write data with this write time applied thereto, to another storage system. The target storage system stores the write data in a logical volume in the target storage system in accordance with the write time.

Abstract: A remote copy system includes a plurality of storage systems. Each first storage system assigns a sequential number to write data received from the host and sends the write data with the sequential number to the second storage system. One of the first storage systems defers the processing of the write request received from the host and instructs each of the first storage systems to create a marker that includes a sequential number that is a marker number. The second storage systems receive the marker from the first storage system and store the marker number included in the marker.

Abstract: A storage control apparatus and a storage control method are provided wherein in a system having a plurality of disk systems and secondary disk systems at remote sites, the data transfer amount between a central processing unit and a disk system can be reduced when duplicate disk write is performed, the performance can be prevented from being degraded even if the distance between control units is elongated, and the intermediate results of a transaction are not left. A standard time is determined and a program is provided which instructs a secondary central processing unit to reflect only update information having a write time older than the standard time, upon a logical disk in the secondary disk system.

Abstract: In a system in which data employed by a computer is stored in a storage system, the storage system transfers this data to another storage system and a copy of the data is maintained in the other storage system, consistency of the copy is maintained even in the case of data written to the storage system by a computer, to which a write time is not applied. A source storage system, when a write time is applied to a write request, records the write time and applies this write time to the received write data and, when no write time is applied, applies the recorded write time to the received write data and transfers the write data with this write time applied thereto, to another storage system. The target storage system stores the write data in a logical volume in the target storage system in accordance with the write time.

Abstract: A server system comprising a plurality of servers that can be each operated as a primary system and a standby system by system switching, and a shared disk unit for storing data accessed by said plurality of servers, wherein: each of said plurality of servers comprises: an application means; a driver means that: acquires information on a configuration inside said shared disk unit after starting of said system; and, based on said configuration information, sets said shared disk unit in an active state in which an access request to said shared disk unit can be sent; and, when the driver means receives an access request to said shared disk unit, sends said access request to said shared disk unit; and an access control means that: judges whether an access request issued by said application means should be sent, based on a management table indicating inhibited types of access requests for each access destination; and sends said access request to said driver means when said access request is not inhibited for an ac

Abstract: In a computer system with a plurality of levels of cache storage, a cache control method prevents data duplication among the levels of cache storage to increase cache storage utilization. A high-level cache staging unit stages reads data from a disk unit, stages the data to a high-level cache, and instructs to destage the data, which has been read, from a low-level cache. A high-level cache destaging unit writes data to be destaged to the disk unit, instructs to stage the data, which has been written, to the low-level cache, and destages the data from the high-level cache. A low-level cache staging unit stages a data, which is written by the high-level cache destaging unit, to the low-level cache. A low-level cache destaging unit destages a data, which is instructed by the high-level cache staging unit, from the low-level cache.

Abstract: In the data transfer method between a couple of computer nodes in the related art, an overhead for the waiting between programs to conduct the data transfer is considerably large.

Abstract: An enqueue structure type is provided within a coupling facility to record the use state and to manage a request queue of resources shared among programs on computers of a system. All programs to use a shared resource issue a request to reserve the shared resource to the coupling facility before using it. The coupling facility affords the permission to use the resource to the programs if it is usable, and adds the programs to the resource request queue if unusable. When a program using the shared resource frees it, the coupling facility fetches a program from the beginning of the request queue, reserves the shared resource for the next program and notifies the next program that the use of the shared resource has been approved. On receiving the notification, the program uses the shared resource without asking the coupling facility for the approval of the use of the shared resource again.